Double spike in the electropherogram of a myeloma serum, from Bence Jones protein

Serum from a 71-year-old man with multiple myeloma complicated with renal failure showed a monoclonal IgG lambda. A second spike appearing in the serum protein electropherogram, suggesting a biclonal gammopathy, was found to be due to lambda Bence Jones protein (29.9 g/liter). Lambda Bence Jones protein was also found in smaller concentration (3.8 g/liter) in the urine. Tetramers of Bence Jones protein were not demonstrable by gel filtration and ultracentrifugation, and renal failure was probably the main reason for this very high concentration of Bence Jones protein in the serum.